In topography the height of the ground is measured at certain points. For example, at 8,848 metres above sea level, Mount Everest is the highest land elevation in the world (the concept of an upper bound) whereas the deepest ocean trench in the world (the concept of a lower bound) has been measured at -10,617 metres.

This page focuses on the topography of sequences giving a few definitions and ways of determining these high and low points (bounds) when they exist.

1.- Move the red points and watch how the highest and lowest points of the mountain and valley/ocean trench change respectively.

This window shows a sequence which has lower bounds.

2.- In your exercise book write down the general term of the sequence, the first five terms, the 20th and 100th terms and observe the behaviour of this sequence.

3.- Look carefully at which numbers are lower bounds of the sequence and which are not.

4.- Write down three lower bounds of this sequence in your exercise book.

This window shows a sequence which has upper bounds. 

6.- Use the K arrows or move the blue point along the y-axis to see which numbers are upper bound and which are not.

7.- Write down three upper bounds for this sequence in your exercise book.

 Click here for more examples.

8.- In your exercise book write down what you think the upper and lower bounds of a sequence refer to.